Zamonia is a rather obscure fantasy world with a cult following, created by German author and cartoonist Walter Moers. It is the setting for such amazing novels as The 13 1/2 Lives of Captain Bluebear, and The City of Dreaming Books. The world is rather silly in the tradition of Terry Pratchett's Discworld, but its novels contain quite a bit of interesting philosophy and drama. They are charmingly illustrated with amusing cartoons, and yet are intended for an adult audience, which is awesome.
The only Zamonia books I have so far read is The City of Dreaming books, in which an anthropomorphic dinosaur visits a city called Bookholm in search of a mysterious author. Bookholm's economy hinges almost entirely on the sale of books, and rests on top of a massive network of book-shelf-laden catacombs containing long-lost libraries and tome-laden tombs. Our hero is marooned in this cave network, and must survive deranged Lovecraftian monsters and amuzingly sadistic traps in order to survive.
Its a lot of fun.
I think it would adapt beautifully to BRP. More so than d20, anyway. The characters aren't really defined by classes, combat is dangerous and gritty, monsters are truly terrifying, there are a vast multitude of useful skills, and much of adventuring isn't combat. All these elements fit perfectly with BRP.